The present invention relates generally to hand-held, manually-operated sanding tools for use with a replaceable sheet of abrasive material such as sandpaper. More particularly, it relates to sanding tools that are easy to load and related methods of use.
Abrasive sheets, such as conventional sandpaper, are commonly used to hand-sand or finish a work surface, such as a wooden surface. With hand-sanding, the user holds the sandpaper directly in his/her hand and then moves the sandpaper across the work surface. Sanding by hand can, of course, be an arduous task. To facilitate the hand-sanding process, the sandpaper can instead be retained by a sanding block or tool sized to fit within the user's hand. The sanding block or tool thus makes hand-sanding faster and easier. One example of a commercially-available sanding block is the 3M™ Rubber Sanding Block available from 3M Company of Saint Paul, Minn.
U.S. Pat. No. 5,168,672 describes another exemplary sanding block or tool in the form of an abrasive sheet holder having a base provided with clamping shoulders formed in a pair of opposed side edges thereof. A handle is detachably secured over a rear surface of the base. The handle has opposed flexible flange walls for clamping opposed end edge portions of an abrasive paper sheet that is otherwise positioned over a front working surface of the base, with the edge portions of the paper sheet extending over the clamping shoulders.
Additionally, U.S. Patent Application Publication No. 2003/0104777 describes a sanding block or tool including a generally rectangular base housing upon which a multi-contoured, generally convex hand-grip is secured. The hand-grip further defines inwardly extending concave portions that facilitate easy and secure grasping by the user. Further, an over-center lever clamp mechanism is operative at each end of the sanding block to secure the opposed ends of a sandpaper sheet in a releasable manner.
While well-accepted, known sanding blocks may have certain shortcomings. For example, it is desirable that the sheet of abrasive material be tensioned or tightly fit about the sanding block. If the sheet is not tight, it may wrinkle, and the wrinkles may snag on the work surface and cause the abrasive sheet to tear. In addition, wrinkles may cause the work surface to be damaged or sanded unevenly. These concerns arise with flexible flat sheets of abrasive material, such as conventional sandpaper, as well as with resilient flexible abrasive sheets that are thicker than conventional sandpaper, such as the sheet-like abrasive materials described in, for example, Minick et al., U.S. Pat. No. 6,613,113. Unfortunately, the mechanisms by which conventional sanding blocks or tools effectuate loading of the abrasive sheet do not consistently achieve the desired, tensioned fit.
In particular, the common technique by which known sanding blocks are loaded with an abrasive sheet generally entails securing opposing ends of the abrasive sheet to opposite sides of the sanding block. With one approach, a user attempts to simultaneously secure the opposing ends of the abrasive sheet to the sanding block while at the same time tensioning the abrasive sheet. This requires considerable dexterity, and often times the user is unable to achieve satisfactory results. Alternatively, the user can sequentially mount a first end portion of the abrasive sheet to one side of the sanding block, wrap the abrasive sheet about a bottom of the sanding block, and then secure the second end portion of the sheet to the opposite side of sanding block. A tension is theoretically created and maintained while wrapping the sheet about the bottom. While this technique is physically easier to perform, it can be equally frustrating for the user. Namely, it is difficult at best to properly estimate the amount (i.e., length) of the first end portion of the abrasive sheet to initially secure to the first side of the sanding block such that when the abrasive sheet is wrapped about the bottom, a proper length remains for securement to the opposing side of the sanding block. For example, if an excessive length of the abrasive sheet is initially secured to the sanding block, there may not be a sufficient length remaining to wrap about the sanding block and secure to the opposing side thereof. Conversely, if too short a length of the abrasive sheet is initially secured to the sanding block, it may be problematic to secure the second end to the opposing side of the sanding block as the excessive, remaining length that interferes with proper functioning of the securement mechanism; similarly, it may be impossible to achieve desired tensioning of the abrasive sheet, again due to the excessive remaining length. In either case, the user is required to release the first end from the sanding block and try again. Clearly, this can be frustrating for the user.
In light of the above, a need exists for a sanding tool that is easy to consistently and satisfactorily load with a sheet of abrasive material in a manner that tightly secures the abrasive sheet.